Page 182 of 290
179 Check regularly and before a long trip
Te ch n i c a l
data Instruments 
and controlsOperationDrivingInstrument 
cluster displayPractical hints Car care Index Check regularly and before a long trip
SLK 230 Kompressor shown1Windshield washer and
headlamp cleaning system
For refilling reservoir, see page 199.
2Coolant level
See “Adding coolant” on page 198.
3Engine oil level
See “Checking engine oil level” on page 197 and 
“Engine oil level indicator” on page 79.
4Brake fluid
See “Brake fluid” on page 268.
Opening hood, see page 194.
Ve h i c l e  l i g h t i n g : Check function and cleanliness. For 
replacement of light bulbs, see “Exterior lamps” on 
page 230.
Exterior lamp switch, see page 81. 
     
        
        Page 190 of 290

187 Malfunction and indicator lamps
Te ch n i c a l
data Instruments 
and controlsOperation DrivingInstrument 
cluster displayPractical hints Car care Index Low engine coolant level warning lamp
With the key in steering lock position 2, the 
warning lamp comes on. It should go out 
when the engine is running.
If the warning lamp does not go out after starting the 
engine, or if it comes on while driving, then the coolant 
level has dropped below the required level. If no leaks 
are noticeable and the engine temperature does not 
increase, continue to drive to the nearest service station 
and have coolant added to the coolant system, see 
page 198.
The low engine coolant level warning light should not be 
ignored. Extended driving with the light illuminated 
may cause serious engine damage not covered by the 
Mercedes-Benz Limited Warranty.
In cases of major or frequent minor coolant loss, have 
the cooling system checked at your authorized 
Mercedes-Benz Center as soon as possible.
Note:
Do not drive without coolant in the cooling system. The 
engine will overheat causing major engine damage.
Monitor the coolant temperature gauge while driving.Low windshield and headlamp washer system fluid 
level warning lamp
With the key in steering lock position 2, the 
warning lamp comes on. It should go out 
when the engine is running.
If the warning lamp does not go out after starting the 
engine, or if it comes on while driving, the level of the 
reservoir has dropped to approximately 1/3 of the total 
volume. The reservoir should be refilled with MB 
Windshield Washer Concentrate “S” and water (or 
commercially available premixed windshield washer 
solvent /antifreeze, depending on ambient temperature - 
see page 199) at the next opportunity. The reservoir for 
the windshield and headlamp washer systems is located 
in the engine compartment.
Wa r n i n g !
Do not spill antifreeze on hot engine parts. 
Antifreeze contains ethylene glycol which may 
burn if it comes into contact with hot engine parts. 
You can be seriously burned. 
     
        
        Page 201 of 290

198 Coolant level
Te ch n i c a l
data Instruments 
and controlsOperation DrivingInstrument 
cluster displayPractical hintsCar care Index
Coolant level
To check the coolant level, the vehicle must be parked 
on level ground and the engine stopped.
Check coolant level only when coolant is cold.
Adding coolant
If coolant has to be added, a 50/50 mixture of water and 
MB anticorrosion / antifreeze should be added. Refill 
coolant until the float in the reservoir reaches and 
closes the filler opening. Anticorrosion / antifreeze, see page 270. The drain plugs for the cooling system are 
located on the right side of the engine block and at the 
bottom of the radiator.
P20.20-2052-26
Wa r n i n g !
In order to avoid possible serious burns or injury:
• Use extreme caution when opening the hood if 
there are any signs of steam or coolant leaking 
from the cooling system, or if the coolant 
temperature gauge indicates that the engine is 
overheated.• Do not remove pressure cap on coolant 
reservoir if engine temperature is above 194°F 
(90°C). Allow engine to cool down before 
removing cap. The coolant reservoir contains 
hot fluid and is under pressure.• Using a rag, slowly open cap approximately 
1/2 turn to relieve excess pressure. If opened 
immediately, scalding hot fluid and steam will 
be blown out under pressure.
• Do not spill antifreeze on hot engine parts. 
Antifreeze contains ethylene glycol which may 
burn if it comes into contact with hot engine 
parts.